Is the Voltage Gate of Connexins CO2-sensitive? Cx45 Channels and Inhibition of Calmodulin Expression

Is the Voltage Gate of Connexins CO2-sensitive? Cx45 Channels and Inhibition of Calmodulin... The sensitivity of Cx45 channels to CO2, transjunctional voltage (V j) and inhibition of calmodulin (CaM) expression was tested in oocytes by dual voltage clamp. Cx45 channels are very sensitive to V j and close with V j preferentially by the slow gate, likely to be the same as the chemical gate. With a CO2-induced drop in junctional conductance (G j), both the speed of V j-dependent inactivation of junctional current (I j) and V j sensitivity increased. With 40-mV V j-pulses, the τ of single exponential I j decay reversibly decreased by ˜40% during CO2 application, and Gj steady state/Gj peak decreased multiphasically, indicating that both kinetics and V j sensitivity of chemical/slow V j gating are altered by changes in [H+]i and/or [Ca2+]i. CaM expression was inhibited with oligonucleotides antisense to CaM mRNA. With 15 min CO2, relative junctional conductance (G jt/G jt0) dropped to 0% in controls, but only by ˜17% in CaM-antisense oocytes. Similarly, V j sensitivity was significantly lessened in CaM-antisense oocytes. The data indicate that both the speed and sensitivity of V j-dependent inactivation of the junctional current of Cx45 channels are affected by CO2 application, and that CaM plays a key role in channel gating. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Is the Voltage Gate of Connexins CO2-sensitive? Cx45 Channels and Inhibition of Calmodulin Expression

Loading next page...
 
/lp/springer_journal/is-the-voltage-gate-of-connexins-co2-sensitive-cx45-channels-and-YFdnubQ0J8
Publisher
Springer-Verlag
Copyright
Copyright © 2003 by Springer-Verlag New York Inc.
Subject
Philosophy
ISSN
0022-2631
eISSN
1432-1424
D.O.I.
10.1007/s00232-003-2044-6
Publisher site
See Article on Publisher Site

Abstract

The sensitivity of Cx45 channels to CO2, transjunctional voltage (V j) and inhibition of calmodulin (CaM) expression was tested in oocytes by dual voltage clamp. Cx45 channels are very sensitive to V j and close with V j preferentially by the slow gate, likely to be the same as the chemical gate. With a CO2-induced drop in junctional conductance (G j), both the speed of V j-dependent inactivation of junctional current (I j) and V j sensitivity increased. With 40-mV V j-pulses, the τ of single exponential I j decay reversibly decreased by ˜40% during CO2 application, and Gj steady state/Gj peak decreased multiphasically, indicating that both kinetics and V j sensitivity of chemical/slow V j gating are altered by changes in [H+]i and/or [Ca2+]i. CaM expression was inhibited with oligonucleotides antisense to CaM mRNA. With 15 min CO2, relative junctional conductance (G jt/G jt0) dropped to 0% in controls, but only by ˜17% in CaM-antisense oocytes. Similarly, V j sensitivity was significantly lessened in CaM-antisense oocytes. The data indicate that both the speed and sensitivity of V j-dependent inactivation of the junctional current of Cx45 channels are affected by CO2 application, and that CaM plays a key role in channel gating.

Journal

The Journal of Membrane BiologySpringer Journals

Published: Sep 19, 2003

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off